import io
import os
import tempfile
import hashlib
import json
import logging
import pandas as pd
from datetime import datetime
from dotenv import load_dotenv
from langchain_community.vectorstores import FAISS
from langchain_openai import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from PyPDF2 import PdfReader
from docx import Document
# from transformers import pipeline

# Load environment variables
load_dotenv()
open_api_key_token = os.getenv('OPENAI_API_KEY')


class FileHandler:
    def __init__(self, vector_db_path):
        self.vector_db_path = vector_db_path
        self.embeddings = OpenAIEmbeddings(api_key=open_api_key_token)
        # self.summarizer = pipeline("summarization")

    def prepare_metadata_string(self, document_name, document_description, department, version, last_updated):
        metadata_string = f"\nDocument Name: {document_name}\nDocument Description: {document_description}\nDepartment: {department}\nVersion: {version}\nLast Updated: {last_updated}"
        return metadata_string

    async def handle_file_upload(self, file, document_name, document_description, department, version, last_updated):
        content = await file.read()
        file_hash = hashlib.md5(content).hexdigest()
        file_key = f"{file.filename}_{file_hash}"
        vector_store_path = os.path.join(self.vector_db_path, f"{file_key}.vectorstore")
        metadata_path = os.path.join(self.vector_db_path, f"{file_key}.metadata.json")

        metadata_string = self.prepare_metadata_string(document_name, document_description, department, version,
                                                       last_updated)

        if os.path.exists(vector_store_path) and os.path.exists(metadata_path):
            with open(metadata_path, 'r') as md_file:
                metadata = json.load(md_file)
            return {'path': vector_store_path, 'metadata': metadata, 'status': 'skipped - duplicate'}

        if file.filename.endswith('.csv') or file.filename.endswith('.xlsx'):
            texts = self.load_and_split_table(content, file.filename,metadata_string)
        else:
            texts = await self.load_and_split_text(content, file.filename,metadata_string)

        vector_store = self.create_vector_store(texts)
        vector_store.save_local(vector_store_path)

        metadata = {
            'filename': file.filename,
            'document_name': document_name,
            'document_description': document_description,
            'department': department,
            'version': version,
            'last_updated': last_updated,
            'hash': file_hash,
            'upload_date': datetime.now().isoformat(),
            'file_path': vector_store_path,
            'file_size': len(content),
            'content_type': file.content_type
        }

        with open(metadata_path, 'w') as md_file:
            json.dump(metadata, md_file)

        return {"message": "File processed and vector store created successfully", "file_metadata": metadata}

    def summarize_text(self, text):
        try:
            summary = self.summarizer(text, max_length=150, min_length=10, do_sample=False)
            logging.info("Text summarization successful")
            return summary[0]['summary_text']
        except Exception as e:
            logging.error(f"Error in summarization: {str(e)}")
            # Log error or handle exception
            return text  # Return original text if summarization is not possible

    def load_and_split_table(self, content, filename,metadata_string):
        # Handle CSV and Excel file reading
        if filename.endswith('.csv'):
            df = pd.read_csv(io.StringIO(content.decode('utf-8')))
        else:  # Excel
            df = pd.read_excel(io.BytesIO(content))
        text = df.to_string(index=False)  # Convert DataFrame to string
        text += metadata_string  # Append metadata to the text
        return self.split_text(text)

    async def load_and_split_text(self, content, filename,metadata_string):
        with tempfile.NamedTemporaryFile(delete=False, mode='w+b', suffix=f"_{filename}") as temp_file:
            temp_file.write(content)
            temp_file.flush()
            temp_file_path = temp_file.name

        # Ensure the temp file is closed before reading from it
        if filename.endswith('.pdf'):
            texts = await self.load_and_split_pdf(temp_file_path,metadata_string)
        elif filename.endswith('.docx'):
            texts = await self.load_and_split_docx(temp_file_path,metadata_string)
        elif filename.endswith('.txt'):
            texts = await self.load_and_split_txt(temp_file_path,metadata_string)

        # Apply summarization here to each text segment
        # summarized_texts = [self.summarize_text(text) for text in texts]

        # os.unlink(temp_file_path)  # Explicitly remove the temporary file
        # return summarized_texts
        os.unlink(temp_file_path)  # Explicitly remove the temporary file
        return texts

    async def load_and_split_pdf(self, pdf_path,metadata_string):
        reader = PdfReader(pdf_path)
        text = ''
        for page in reader.pages:
            text += page.extract_text() or ""
            text += metadata_string  # Append metadata to the text
        return self.split_text(text)

    async def load_and_split_docx(self, docx_path,metadata_string):
        doc = Document(docx_path)
        text = '\n'.join([paragraph.text for paragraph in doc.paragraphs if paragraph.text])
        text += metadata_string  # Append metadata to the text
        return self.split_text(text)

    async def load_and_split_txt(self, txt_path,metadata_string):
        with open(txt_path, 'r', encoding='utf-8') as file:
            text = file.read()
            text += metadata_string  # Append metadata to the text
        return self.split_text(text)

    def split_text(self, text):
        text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
        return text_splitter.split_text(text)

    def create_vector_store(self, texts):
        return FAISS.from_texts(texts, self.embeddings)